This invention relates to the destruction of microform materials, especially those of a confidential or classified nature. More particularly, this invention concerns itself with a thermal technique for effecting the rapid destruction of microform materials.
The storage, retrieval and distribution of information of a technical nature has become a problem of great importance in light of the many advances made in virtually all areas of science and technology. One system which has found wide acceptance, involves the use of low cost, high quality microforms such as microfilms, microfiche, aperture cards or roll and cartridge film. The use of microforms allows high quality information to be maintained in a minimal amount of space at various locations, thus maximizing the potential use of the information by scientists and technologists. Also, the ready availability of information and its easy retrieval has great military potential, since it materially assists in the mobilization and operation of tactical units especially at the field operational level. However, military type information is often of a confidential nature. Therefore, a method for its rapid destruction must be provided in order to avoid a possibile compromises within a hostile environment.
As a consequence, a number of approaches have been suggested for accomplishing the rapid destruction of microforms. One effective method involves destruction by burning and is referred to as the pyrolytic method. Theoretically, this method should result in the complete destruction of the microform. Unfortunately, pieces of film can sometimes be recovered from the ash. Another method involves mechanical destruction with shredders or pulverizers. This method, however, requires the use of large pieces of equipment that require constant attention and maintenance and are not easily adaptable for use in aircraft or mobile vans due to the problems associated with their size.
The chemical destruction of microforms, such as stripping, is still another method. When utilized however, strict health, safety and environmental guidelines must be adhered to. Also, in the chemical stripping of films, the machines used to accomplish the stripping are large and cumbersome. Furthermore, not all chemical systems are useful for destroying the various types of film supports and emulsions used in fabricating the microform material since the specific chemcial relied upon is often selective in nature and only destroys a specific type of film.
The methods of destruction referred to above and presently in use have not provided a solution to the problem of rapidly destroying the classified microforms used by military planners, especially at the field operational level where time and space allocations are at a minimum. With the present invention, however, a thermal method has been found that provides for the destruction of the various types of microforms in a rapid and efficient manner. Destruction of the microforms is accomplished by using a silicon oil heated to 250.degree. C. to effect the destruction of the film. The silicone oil is preferably placed in a one-drawer field safe although any suitable container could be used. Destruction of the various types of microform products is accomplished effeciently and economically in five minutes or less. All evolved gases are scrubbed before discharge into the environment.